Eroare de compilare: user.cpp: In function ‘void back()’: user.cpp:29: warning: suggest explicit braces to avoid ambiguous ‘else’ user.cpp: In function ‘int main()’: user.cpp:44: error: ‘ifstream’ was not declared in this scope user.cpp:44: error: expected ‘;’ before ‘f’ user.cpp:45: error: ‘ofstream’ was not declared in this scope user.cpp:45: error: expected ‘;’ before ‘g’ user.cpp:46: error: ‘f’ was not declared in this scope user.cpp:48: error: ‘g’ was not declared in this scope